I've been working on subsonic cast lead loads for my 10.5" suppressed 458 socom SBR, pistol length gas system. My goal was a round that was quiet, cycled, ran clean, and was fairly accurate. So far, so good with 300 and 405 grain cast lead RNFP, these are not gas checked or coated.
My experience with TrailBoss powder has been excellent, it burns clean, doesn't smoke to bad, and gives consistent velocity. My only problem is accuracy, and that's more than likely all on me, and my dies, I'm using a Lee three die set that's seen allot of rounds over the years. An upgrade is needed soon!
All these loads have been with Sellier&Bellot large pistol primer, slight crimp with my Lee seat die, and a COL of 2.09".
300 grain cast lead RNFP, I've had the best accuracy with 12.7 grains, average velocity was 1068 with a standard deviation of 7.
Suppressed 458socom 150 yards - YouTube
405 grain cast lead RNFP, I've had the best accuracy with 12.8 grains, average velocity was 949 with a standard deviation of 4.
458socom subsonic load development - YouTube
Suppressed 458socom 405gr RNFP - YouTube
I will continue to work on my accuracy with these, I'll update with any info, and data I find. If you have any thing to add or share please do so, I would love to hear if anyone with carbine or mid-length gas rifles have any luck with these loads.
Please follow Hodgdons directions on loading with TrailBoss powder, these loads were developed with my rifle, you may have very different results.
My experience with TrailBoss powder has been excellent, it burns clean, doesn't smoke to bad, and gives consistent velocity. My only problem is accuracy, and that's more than likely all on me, and my dies, I'm using a Lee three die set that's seen allot of rounds over the years. An upgrade is needed soon!
All these loads have been with Sellier&Bellot large pistol primer, slight crimp with my Lee seat die, and a COL of 2.09".
300 grain cast lead RNFP, I've had the best accuracy with 12.7 grains, average velocity was 1068 with a standard deviation of 7.
Suppressed 458socom 150 yards - YouTube
405 grain cast lead RNFP, I've had the best accuracy with 12.8 grains, average velocity was 949 with a standard deviation of 4.
458socom subsonic load development - YouTube
Suppressed 458socom 405gr RNFP - YouTube
I will continue to work on my accuracy with these, I'll update with any info, and data I find. If you have any thing to add or share please do so, I would love to hear if anyone with carbine or mid-length gas rifles have any luck with these loads.
Please follow Hodgdons directions on loading with TrailBoss powder, these loads were developed with my rifle, you may have very different results.
